2021 IECC: A Code on a Mission – Campaign Toolkit

This Code on a Mission Toolkit supports communities and advocates with adoption of the 2021 IECC and it’s appendices and consideration of the 2021 IgCC. The toolkit includes the following resources:


Reasons for adopting the 2021 IECC

2021 IECCCommunities that regularly adopt the IECC save money for residents and business and improve community health and resilience. Some jurisdictions routinely augment the most recent model code with additional energy-saving code provisions or programs.

States are required to review their residential energy code and update their commercial energy code within two years of a positive determination from the Department of Energy that a new edition of the IECC saves energy.

Reasons to adopt the 2021 IECC fall into two categories: Energy Efficiency Improvements and New and updated provisions save energy, improve usability.

Energy Efficiency Improvements

On July 21, 2021, DOE Pacific Northwest Laboratory (PNNL) produced a final determination on the 2021 IECC representing a 9.4% site energy savings improvement and an 8.7% improvement in carbon emissions for residential buildings relative to the 2018 IECC, saving homeowners an average of $2,320 over the life of a typical mortgage.

DOE’s final determination can be found here.

The 2021 IECC represents an approximately 40% improvement in energy efficiency for residential and commercial buildings compared to the 2006 edition, meaning that residents in states and cities on older IECC editions would see far greater savings. The Department has also released data on energy, cost and GHG reductions each state and many cities could achieve by adopting the 2021 IECC, which are available here.


New and updated provisions save energy, improve usability

Key changes to the 2021 IECC improve efficiency by 9.4 percent and reduce greenhouse gases by 8.7 percent over the 2018 IECC; these changes include new provisions that increase efficiency and encourage greater flexibility in design and construction as well as changes to existing requirements that provide clarification and improve usability of the code.

View a summary of key changes here.

Additional Energy Efficient Packages

Three new additional energy efficient package options, as shown in the figure below, were added to the 2021 IECC. This addition brings the total number of energy efficiency compliance options to eleven. The purpose of this section is to provide flexibility to achieve the energy savings needed to meet the overall energy savings goal of the code. These additional requirements come into play during the design phase where the designer has chosen the Prescriptive Compliance option. Where a designer pursues compliance via meeting ANSI/ASHRAE/IESNA 90.1 or is using the Total Building Performance approach, then Section C406 does not need to be addressed.

New Tropical Climate Zone Compliance Path

Tropical areas vary from the United States mainland in climate, construction techniques and energy prices. The new Tropical Climate Zone Compliance Path recognizes traditional tropical design characteristics encompassing shading, natural ventilation and the value of cool roofs. Mainland U.S. residential construction trends can minimize fenestration area, rely on dark roofing materials and overlook the value of external shading. Applied in tropical regions, these mainland construction trends result in overheated dwellings where natural ventilation is ineffective, yet the buildings lack the insulation and air sealing appropriate for any conditioned space. Additionally, tropical electrical prices make air conditioning infeasible for many households and, likewise, provide a substantial incentive for energy conservation.

Adoptable Appendix for Net Zero Energy Buildings

The 2021 IECC includes Zero Code appendices for both residential and commercial buildings.

The residential Zero Code appendix is based on the Energy Rating Index (ERI) path of the code, which requires more efficiency than is required in the base code and requires enough onsite or offsite renewable energy production to achieve an ERI score of zero. Renewable energy compliance may happen through a combination of onsite power production, energy generated through community renewable energy facilities, and renewable energy purchase contracts or leases.

The commercial Zero Code appendix is based on the Architecture 2030 ZERO Code. It requires a building to meet the minimum code requirements, plus enough on-site or off-site renewable energy to compensate for all the energy anticipated to be consumed by the building.

The Net Zero Energy provisions included in the 2021 IECC are not mandatory unless specifically referenced in the adopting ordinance. The provisions are included as appendices with the intention to provide options for jurisdictions with ambitious climate goals.

More information on Net Zero Energy – Building Operation Decarbonization can be found here.

Compliance and Enforcement

Each new edition of the energy code has provided for the cost-effective reduction of energy use. Implementation of the 2021 IECC is foundational to achieving energy savings and reductions on GHG emissions across building stock, both residential and commercial. According to the US Department of Energy, from 2010 to 2040, the model energy codes for residential and commercial buildings are projected to save:

  • $138 billion energy cost savings
  • 900 MMT of avoided CO2 emissions
  • 13.5 quads of primary energy

These savings equate to the annual emissions of:

  • 195 million passenger vehicles
  • 227 coal power plants
  • 108 million homes

For perspective, the primary energy consumption of the entire U.S. commercial and residential sectors in 2020 was estimated at 38 quads.

Adoption of the most recent model energy code is the first step to tapping into to cost-effective energy savings. Adoption should be followed by training and full implementation of the adopted code.

Although there is significant evidence of the value of energy code implementation, studies also show millions of dollars of untapped energy savings in states across the country. DOE has also observed, across 7 states studied, that training code officials on adopted codes can help reduce annual energy costs due to varying levels of code compliance by an average of about 45 percent.

Assessing the current construction practices, establishing compliance and enforcement goals, and accessing intake plan review inspection tools are the first steps to successful compliance and enforcement. Training requirements are equally important. The gap that exists between the efficiency levels required in codes and the efficiency levels achieved in the field is influenced by the extent of code official training on the energy code. Although about two-thirds of states require code official certifications, only seven states require training on energy code provisions.

More information on IECC Compliance and Enforcement can be found here.

Considerations for Adopting the 2021 IgCC

The International Green Construction Code (IgCC) is a collaborative effort of the Code Council, ASHRAE, the Illuminating Engineering Society and the U.S. Green Building Council to provide adoptable code language for communities that want to go beyond requirements contained in base codes. Although a stretch code currently, the IgCC sets the direction for the future of high performance building. The IgCC provides the design and construction industry with the single, most effective way to deliver integrated energy conservation, water efficiency, site and material sustainability, land use, and indoor environmental quality. It is currently adopted or in use in 13 states and DC and by the General Services Administration and the Department of Defense.

The 2021 edition of the IgCC offers essential sustainable construction building blocks on which future resilient initiatives can develop and expand. As jurisdictions continue to go beyond base codes to meet their robust climate and energy efficiency goals, the IgCC will be a critical part of the toolkit. The new edition provides:

  • Written-in, enforceable code language and overlays with I-Codes;
  • Extended scope to all areas of sustainable buildings and sites beyond energy conservation provisions of the IECC;
  • Ability to customize which requirements to adopt through a Jurisdictional Options table;
  • Appendix L, which aligns IgCC requirements with core elements of LEED versions 4.0 and 4.1;
  • Appendix M, which provides options for residential compliance with the National Green Building Standard (ICC 700).

Social Media Resources

Here are eight digital cards that you can post on social media that showcase the energy savings and efficiency of the 2021 International Energy Conservation Code®. Each card is available in 1200x630 and 1080x1080 dimensions for a total of 16 cards.


Partner Resources

Northeast Energy Efficiency Partnerships (NEEP)